docs: def check_permission(instance, field, permission):
      """
      Check a permission for a given instance or field.  Raises an error if
      denied.
  
      :param instance: The instance to check
      :param field: The field name to check or None for instance
      :param permission: The permission to check
      """
      if not get_permission_test(instance, field, permission)(instance):
          raise PermissionDeniedError(permission, instance, instance, field)